Post from a Scientist: Cascading Ice


Shorts on an Alaskan glacier

In Oregon, where I grew up, agriculture thrives in part because of seasonal snow storage in the Cascade Mountains, which melts into the river system in late spring and summer and provides water during the portion of the year when there’s little rain in the valley.  The Willamette Valley, which is on the western side of the Cascades, is also extremely fertile due to the sediment deposits left behind by glaciers that were present in the region thousands of years ago.  The region I am studying for my PhD research is the Karakoram and Himalayan Mountains in Asia, which, like the Cascade Mountains, store water for future use.  Hundreds of millions of people in India, China, Pakistan, and Nepal live downstream of the Karakoram and Himalayan Mountains and rely on water from the mountains for most aspects of life.

The Karakoram and Himalayan Mountains are extremely steep and contain many of the highest peaks in the world. The Karakoram and Himalaya Mountains have many more glaciers than the Cascades, which have been storing water for thousands of years.  In addition to being a natural reservoir of water, the glacial sediment mixed into the glacier melt water helps fertilize the downstream agriculture.

Climate change is affecting both the seasonal snow storage and the longer-term storage by the glaciers.  So far in my research, I’ve focused on modeling projections of future snowfall in the regions, and have found that annual snowfall in the region may decrease by 20 to 50%, depending on how much the climate changes.  These changes in snowfall are caused by increases in temperature and changes to precipitation, which will also impact glacier mass in the region.  My future work will be to model projected changes to the glaciers, then combine this with the snowfall projections and other important hydrological processes, to model climate change affects on river water availability.

Any significant changes to the water availability in this region will be potentially disruptive for the hundreds of millions of people living downstream.  By understanding these changes before they happen, we can work to minimize the drivers behind the changes and mitigate the impacts of them.  Through this understanding and preparation for the likely changes, hopefully all of us – the people living downstream of the Karakoram, Himalaya, and Cascade Mountains – can continue to have plentiful water resources and glean all the other benefits of having healthy glaciers.

- Thomas, Oregon State University, USA

This entry was posted in scientist post and tagged . Bookmark the permalink.

2 Responses to Post from a Scientist: Cascading Ice

  1. David says:

    While the glaciers in Asia are melting there will be lots more water coming down from the mountains. I heard in my geography class that there are lots of dams just made of dirt that could break from all that water. Is that true? And once the glaciers are all gone, really how can all those people get enough water?

    • Thomas says:

      Hi David, I’m not an expert in dams and don’t have an up-to-date inventory of infrastructure in the region, so I can’t really speak to that part of the question.

      With regards to the affects of glacier mass balance on stream water availability, here’s a recent paper ( on the topic. The model used by Lutz et al. (2014) depicts increases through 2050 in runoff due both to increased precipitation and increased glacier melt. This certainly will have implications for water management in the region. As an interesting note, if the mass balance of glaciers are in steady-state (i.e. neither growing or shrinking), there wont be a net annual affect on downstream water availability. So, if the glaciers were gone completely, the main change in water resources relative to historic steady-state levels would be the seasonality of stream water availability.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>